In certain motor applications, the motor must start and stop quickly and repetitively. Such is the case in motors used to drive presses such as crimping presses. The motor must be started for each cycle and stopped at the end of the cycle. The longer the stopping time, the longer the time between cycles and the greater the number of revolutions of the motor required between cycles.
One known method for actively braking an AC motor is known as DC injection braking. In DC injection braking, a DC current is injected across the windings of the AC motor to create an electromagnetic force that acts on the motor rotor, forcing the rotor to stop rotating.